Audible synchronism-indicator



(No Model.)

B. D. MERSHON. AUDIBLE SYNGHRONISM INDIOATOB.

Patentd Nov. 20, 1894.

WITNESSES: g

A 'ITORNE Y5.

UNITED STATES PATENT Ornicgn.

RALPH DIMERSHON, OF PITTSBURG, PENNSYLVANIA.

AU'DIBLE SYNCHRONlSM-INDICATOR.

SPECIFICATION formingpart of Letters Patent No. 529,398, dated November20, 1894.

Application filed April 27, 1 894. Serial No. 509,222. (No model.)

To aZZ whom it may concern.-

Be it known that I, RALPH D. MERSHON, a citizen of the United States,residing in Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in AudibleSynch'ronism-Indicators or Synchrophones, (Case No. 590,) of which thefollowing is a specification.

My invention relates to a method and means whereby alternating currentmotors or generators may be synchronized before connecting them incircuit with each other.

The object of my invention is the provision of aform of synchronizingdevice or synchronism indicator, which shall appeal to the ear of theoperator, so that his eyes need not be removed from his switches at anytime, and so that the indicator may be placed in any desired situationwith respect to the motors or generators to be synchronized and to theswitch whereby they are thrown in circuit.

My inventiondepends upon the opposing eifect of two magnetic poles upona diaphragm, said magnetic poles being created by currents generated bythe electromotive forces across the terminals of the machine to besynchronized.

My invention is illustrated in the accompanying drawing which showsdiagrammatically the relation of the magnetic fields to the diaphragmand the circuits from the machines.

The machines to be synchronized may be two generators or a generator anda motor, and this synchronizing may be for various purposes. In anyevent each machine to be synchronized is driven by some external forceand therefore produces potential across the mains from the machine. Theproblem is to get the two machines into what is known as synchronism, orto make them revolve at approximately the same rate of speed, and tocause the occurrence of maximum potential. to be simultaneous inthe twocircuits.

In the drawing, 1 and 2 represent the two machines to be synchronized.These may be in the same station when the circuits shown in full lineswill be appropriate for the oper= ation of the synchronizer; or onemachine may be at a considerable distance from the other, as whensynchronous motors far from the source of current are to be brought upto synchronism. In this latter case the circuits shown in dotted linesand derived from each side of the switch 3 will be appropriatelyemployed, as it would not be convenient to carry an extra circuit fromthe distant generator. Itwill, of course, be understood that the dottedline circuits are equally appropriate to the first case above-mentioned.

In the practice of my invention I employ two magnetic poles, as forinstance, those produced by the cores 4 and 5. Subject to the influenceof both poles and equally afiected by each is the vibrating polarizeddiaphragm 6, which, for the purpose of increasing the sound, I prefer toplace on or in a sounding box 7. This diaphragm may be constructed inany manner well known to the telephone art, the polarity lyingacross thediaphragm. The cores 4 and 5 are surrounded by coils which are incircuit with the fine wire circuits 8 and 9 respectively or with thedotted line circuits 10 and 11, as above stated. In operation of thesedevices, the motor or generator 2 to be brought into synchronism withthe machine already running will producealternating electromotive forceat the terminals of the coil 5, which may be represented by a wavehaving a certain relation to the electromotive force wave produced bythe machines, both as to height of Wave and 'as to frequency ofvibration. Supposing the height of the waves, or in other words,themaximum electromotive force, to be the same in the two circuits, theoccurrence of synchronism will be indicated by one of two conditions inthe diaphragm depending upon the connection of the coil 5 in one or theother relation with the terminals of the machine 2. The relation whichshould exist between the circuits of the two machines at the moment whenthe switch 3 is thrown is that of exact opposition between therespectiveelectromotive forces, and at the same time the frequency ofthe alternations must be the same or very nearly the same in the twocircuits. It will thus be seen that this required condition will producebe a succession of coincident magnetic actions due to'these two cores.In the latter case the diaphragm will be strongly vibrated by theinfluence of the magnetic action and the maximum of sound due to thevibration of the diaphragm will be the result. It will thus be seen thatthe operator who desires to throw the switch at the moment ofsynchronism has only to wait for the instant .of silence or for theinstant of maximum s und of the diaphragm 6, according as theconnections of the circuit 11 are made in one way or the other with thecircuit from the machine 2.

Where the maximum potential across the mains from the machine 2 is notequal to that from the machine 1, or in other words where the wavesrepresenting the electromotive forces of the two machines have difierentheights, the operator will throw the switch 3 on the occurrence ofminimum sound produced by the diaphragm instead of on the occurrence ofsilence, since the opposing actions of the two cores 4 and 5 will neverin this case be quite equal and thereforesome vibration of the diaphragmwill always occur.

. It should be stated here that the absence of sound recurs at-regularintervals intervening between an increase or decrease-of sound formingwhat may be called a beat. These beats occur at progressively greaterintervals of time as the machine comes intosynchro- I nis m and themoment of silence or maximum sound which is chosen for throwing theswitch should be when these beats are attheir slowest.

. Iam aware of the existence of a form of connected with one of themachines to be synchronized. I therefore do not claim this invention,but desire to call attention to the fact that the invention describedherein differs therefrom in that my present invention depends upon themechanical interference of two distinct magnetic poles as distinguishedfrom the magnetic interference of two fields in the production of onemotor ole.

p I have not elaborated any particular details in the description andillustration of my invention herein, and do not desire to be understoodas confining myself to the precise construction as illustrated anddescribed herein.

What I claim is 1. The method of indicating the'occurrence ofsynchronism between two circuits which consists in converting theelectric vibrations in the two circuits intocorrespondingnmag neticvibrations,thereby producing two distinct magnetic poles and subjectinga polarized body. capable of vibration, to the action of said poles,substantially as described.

,2. 'In a synchronism indicator, a polarized diaphragm, a magnetic coreor cores presenting two poles thereto and two coils connected with theterminals of the machines to be synchronized, each of said coilsproducing one of the actuating poles, substantially as ,described.

In testimony whereof I have hereunto subscribed my name this 11th day ofApril, A. D. 1894.

R. D. ME'RSHON.

Witnesses:

JA ES W SMITH,

HAROLD S.v MACKAYE.

